GTL Exhaust Woes

[Sage103]

I've had my GTL for about 5 years and it has been garaged while I occasionally found time to tackle some of its issues. During this time I've also been collecting parts - mainly off eBay. Now I'm taking a bit of time off work, a trial retirement, and hope to get the car on the road this summer.
First task is to get the engine started again - it hasn't run for a couple of years - and so I've been fitting all the nice shiny exhaust parts I've managed to collect - all except the back box needed renewing - but I've encountered a snag in that the new parts don't quite match the old (and, of course, the old were binned when removed some time ago). Where the pipes should join behind the front wheel arch they don't and an existing underfloor attachment forward of the rear wheel arch is missed by the new pipe. The attached pics show these 2 issues.
I will be able to modify the under-arch pipe to allow it to meet the underfloor pipe so I'm not stuck but just posting this as a warning to check replacement exhaust parts against the old!
And while I'm in that area the 3rd pic shows the nearside chassis leg which appears to have some kind of repair - possibly the cavity has been filled with some kind of material. Has anyone seen anything like this? It all looks and sounds solid and the offside leg looks fine. But will the MOT tester have issue with it?

 

[Renault18]

There are two types of system for the GTL (actually there are three - very early GTLs had an underwing silencer, but that was only for the first cars)

The front pipe which fits under the wing and the long pipe which runs the length of the car are different. One set of part numbers run up until 1983, then the rest for models made after then. Renault modified the pipes I think to comply with legislation, as the later cars had the pipe set slightly further inwards with the mountings also brought to the inner edge of the pipe (away from where sharp edges could be on the outer side)

The new pipe in your picture is the first type. The later one has no curve at the front - it is the pipe under the wing which has the end modified to have the curve. This explains why there is the old mount showing in picture 2, because the metal mounting plate on your pipe is on the wrong side for what I assume is your later car.

You need Renault parts 7700 757 174 (front pipe under wing) and 7700 757 178 (long pipe) for your car. Both parts are still freely available from Renault and cost £27.34 each retail. The rear silencer is best from MisterAuto.co.uk as a Walker part at £21 - Renault use this same part and supply it for £112!!

Hope this helps!!

 

[Tomcat]

Is this of any assistance?

 

[mr-reno-139]

Was told the reason exhaust moved inwards 83 onwards to enable lifting car on 2 post lift and enabling lifting pads to fit corners of floor pan jacking points without squashing pipes

 

[Sage103]

Many thanks for these responses - it appears that I only need to replace the underfloor pipe (it's an 86-registered car).